(1) Field of the Invention
This invention relates to semiconductor device package, in particular to the heat sink of the package.
(2) Description of the Related Art
As semiconductor technology progresses, the semiconductor chip becomes smaller and smaller, the integrated circuit becomes denser and denser, and the chip generates more and more heat.
FIG. 1 shows the top view of a prior art package. FIG. 2 shows the side view of FIG. 1. A semiconductor chip 10 is mounted on a heat conducting metal layer 12 over a substrate 14. The heat conducting metal 12 conducts away the heat generated from the chip 10.
Such a conventional packaging technique is inadequate to accommodate the high heat dissipation of modern high density integrated circuit. A low thermal impedance is needed to prevent the chip to reach an excessive temperature.
Take a light emitting semiconductor chip for instance. The high brightness requirement of the chip dictates that the chip generates a great deal of heat. This heat must be removed to prevent any damage to the chip. Therefore, the ability to remove the heat is directly related to the brightness which the chip can attain. Therefore, the thermal impedance is directly related to the ability to achieve brightness. Such is the goal pursued by the semiconductor industry.